Bayer was the first to introduce Vulkollan to the market in the 1950's, developed from Otto Bayer's discovery in 1937.
Resistance and properties:
This is on the market in various forms. There are millable types that may be processed like many other elastomers, but that need considerably more time to vulcanize, and the liquid versions. The hot-vulcanizable types possess better mechanical characteristics than the millable types, but these liquid types also have a long vulcanization (curing) time. High tear strength, high abrasion resistance. Outstanding weather resistance and resistance to oxidation. Polyurethanes are resistant to hydrocarbons and mineral oil. Hydrolysis, water resistance, is poor, but better up to +60 deg C in the case of polyether polyurethane. The polyether version of the polyurethanes also show the highest low temperature resistance up to around -35 deg C. Unusual for this rubber is that the higger the hardness, the better the mechanical properties. Can normally be used up to around 80deg C, although a particular composition can be used up to around 150 deg C for a brief period.
Among the elastomers, polyurethane shows the greatest resistance to high doses of ionising radiation. A point to note is that, in the event of high-energy radiation doses, polyurethane must not be adhered to aluminium, as an acid is produced that attacks aluminium.
One disadvantage of this elastomer is that it loses heat poorly and thus builds up heat. Temperature resistance and hydrolysis resistance are further weak points.
In situations where abrasion is high or where large forces are generated.